A wireless low-power, high-quality EEG headset

October 10, 2012

Imec’s wireless EEG headset (credit: Imec)

Imec, Holst Centre and Panasonic have developed a new prototype of a wireless EEG (electroencephalogram, or brain waves) headset designed to be a reliable, high-quality and wearable EEG monitoring system.

The system combines ease-of-use with ultra-low power electronics. Continuous impedance monitoring and the use of active electrodes increases the quality of EEG signal recording compared to former versions of the system.

How it works

The EEG data is transmitted to a receiver located up to 10 meters away. The headset integrates active electrodes (reduce the susceptibility of the system to power-line interference and cable motion artifacts to improve signal quality), EEG amplifier, microcontroller, and low-power wireless transmitter.

The receiver can continuously record 8-channel EEG signals while concurrently recording electrode-tissue contact impedance (ETI), a measure of contact quality.

The system has a high (>92 dB) common-mode rejection ratio (to reduce interference from power lines and other sources) and low noise (<6 µVpp, 0.5-100Hz), with configurable cut-off frequency (to filter out high or low frequencies).

The heart of the system is the low-power (750µW) 8-channel EEG monitoring chipset. Each EEG channel consists of two active electrodes and a low-power analog signal processor. The EEG channels are designed to extract high-quality EEG signals under a large amount of common-mode interference. The active electrode chips have buffer functionality with high input impedance (1.4GΩ at 10Hz), enabling recordings from dry electrodes, and low output impedance reducing the power-line interference without using shielded wires

The system is integrated into imec’s EEG headset with dry electrodes, which enables EEG recordings with minimal set-up time. The small size of the electronics system, measuring only 35mm x 30mm x 5mm (excluding battery), allows easy integration in any other product.